There are some cases where an application will print text in opaque mode which can cause problems when using letterheads. Opaque text handling is set as follows:
The reg setting that controls this is a DWORD value called
AllowOpaqueText, located in:
HKCU\Software\FinePrint Software\FinePrint7\FinePrinters\printer_name
HKCU\Software\FinePrint Software\pdfFactory4\FinePrinters\printer_name
The default value is 1, which means “honor the background mode setting that the app requested”. Setting this value to zero means “treat all text output as TRANSPARENT”.